Blender 2.80 Beta wierd vewport behavior
This Issue is Clipping related, at a certain distance surfaces can't get drawn. Imagine the camera as a "plane" that you're moving into the Object. Whats infront, gets shown, whats behind is occluded. 

To fix this issue it is recommended to change the units you use in Blender. You can find them in the Properties Editor -> Scene -> Units :



By default this value should be at "1.000"
 - Change it to "0.1"
You will notice no change, except a change in the "numeric" size of your model. 

After this, you scale up your model by a factor of 10, the model is "bigger" but still has the desired measurements and has no visibility issues.